Introduction The INSIGHT registry is a prospective multicenter registry to collect and analyze clot and blood retrieved during aspiration thrombectomy or hematoma evacuation. This registry will examine whether clot composition and genetic and proteomic variables can provide insight into thrombus etiology or affect clinical outcome. The purpose of this subset analysis is to examine the relationship between clot composition and procedural results for ischemic stroke aspiration thrombectomy.

Materials and Methods All participants who underwent aspiration thrombectomy for ischemic stroke were included in this subset analysis. Clot, blood, and baseline and procedural data were collected. Retrieved clot fragment composition was categorized on the basis of gross appearance.

Results Of 400 participants at 25 US sites, the mean age was 68.9 years (SD 14.8 years), 206 (51.5%) were female, 388 (97.0%) underwent aspiration thrombectomy for ischemic stroke, and 12 (3.0%) underwent endoscopic intracranial hematoma evacuation. Retrieved clot fragments and blood from all participants will be analyzed via histology (n = 385), RNA sequencing (clot, n = 350; blood, n = 377), proteomics (clot, n = 363; blood, n = 378), and single nucleotide polymorphism genotyping (blood, n = 399).

For the 388 participants who underwent aspiration thrombectomy for ischemic stroke, 10 different Penumbra aspiration catheters ranging from 0.035’ to 0.072’ bore diameter were used. The clot composition categories were firm red clot, 165; soft red clot, 151; firm white clot, 37; and soft white clot, 18 (table 1). In most participants (292, 75.3%), the first pass was performed with a direct aspiration first pass technique (ADAPT) without a stent retriever. Clot was extracted with the first pass in 213 (54.9%) participants. The total number of passes for the target lesion was 1.9 (SD 1.3). After the first pass, a modified treatment in cerebral ischemia grade (mTICI) of 2b to 3 (mTICI 2b-3) was observed in 251 (71.1%) participants and mTICI of 2c to 3 (mTICI 2c-3) was observed in 184 (52.1%). At the final angiogram, mTICI 2b-3 was observed in 380 (97.9%) participants and mTICI 2c-3 was observed in 287 (74.0%). Results varied with clot composition, but no significant difference was detected between the clot composition subgroups for mTICI 2b-3 after the first pass (P = .55).

Conclusions Clot removed during neuroendovascular procedures can differ in consistency and removability, leading to an increased focus on thrombus composition as a crucial variable for improving outcomes of ischemic stroke. In this study, good final revascularization (mTICI 2b-3 at the final angiogram) occurred after aspiration thrombectomy regardless of clot composition. Ongoing analysis of collected specimens is expected to provide valuable information regarding thrombus biology and etiology and to aid in diagnosis, prognosis, and drug development.

Disclosures C. Kellner: 1; C; Penumbra, Integra, Cerebrotech, VizAI, Siemens, Minnetronix. A. Dabney: 6; C; SAB member for the INSIGHT study. S. Baltan: 6; C; SAB member for the INSIGHT study. F. Sohrabji: 6; C; SAB member for the INSIGHT study. K. Pennypacker: 6; C; Co-owner of Cerelux. A. Nanda: 6; C; SAB member for the INSIGHT study. K. Woodward: None. D. Rivet: 2; C; Medtronic. J. Fraser: 2; C; Stream Biomedical, Penumbra, Medtronic. 6; C; Co-owner of Cerelux, Equity owner of Fawkes Biotechnology.